|
North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Malicious DNS request?
On Thu, 12 May 2005 16:43:07 +0200, Brad Knowles said: > At 12:41 PM +0400 2005-05-12, Gadi Evron quoted Joe Shen: > > I'd suggest dropping requests for domains you don't hold. > That's kind of hard to do if you're running a recursive/caching nameserver. Well.. are you running a recursive/caching nameserver for everybody on the internet to use, or only for your customers? If the request isn't from inside your address space, and it's a "recursion requested" for a zone you don't hold, maybe they're asking the wrong DNS server. (And yes, I know that if you have a roaming user who's outside your address space but has hard-coded your DNS IP's in their resolv.conf, it gets trickier. The right answer here depends on your customer base.) It's often suggested that you have *two* DNS setups - one that only answers requests from inside for recursion and caching, and an authoritative one that faces out and refuses to recurse. The inside one will cache the outside one fast enough in most environments. (No, this doesn't stop all the possible DNS malfeasance, but it certainly raises the bar a good chunk...) Attachment:
pgp00017.pgp
|